This invention relates to polyethers and more particularly to energetic polyethers containing azido groups.
Azido compounds and polymers are important in the fields of explosives and propellants because the azido group is highly energetic and relatively small in size. The size of the azido moiety imparts excellent polymer properties to the compound and enhances compatibility in polymer systems. An example of how the azido group improves the physical properties of a compound is found in U.S. Pat. No. 3,946,051, issued on Mar. 23, 1976 to James N. Haynes. The compounds are azido formates of omegahydroxyalky phthalates and their condensation polymers. Due to the largeness of the compounds in relation to the azido group, the compounds are considered nonenergetic. Their use is primarily as a surface modifying agent in order to improve the adhesive properties of polyesters.
Few energetic polymers are suitable for compounding propellants because of the severe physical-property requirements of propellants. The polymer must be capable of holding large quantities of solid ingredients as well as plasticizers. The polymers should have a low viscosity in order to facilitate propellant mixing, casting, and have a long pot life. The polymer should have exceptional thermal and chemical stability so that an explosive or propellant composition would have a long shelf life and good reliability. The polymer should also have a low sensitivity but a high energy content.
Wayne R. Carpenter, J. ORG. CHEM, 27, P. 2085+ at 2086, discloses 3,3-bis(azidomethyl)oxetane. Milton B. Frankel, et al in U.S. patent application Ser. No. 237,837, filed on Feb. 25, 1981, entitled "Azido Polymers and Preparation Thereof," disclosed the polymerization of 3,3-bis(azidomethyl)oxetane to form an energetic polymer possessing desirable properties.
Nevertheless, it would be desirable to provide polymers possessing still better properties such as thermal and impact stability and workability. In particular, it would be desirable to provide polymers in which the azido groups are attached directly to the polymer backbones.